Relationship Between Coefficient of Parentage and Genetic Similarity Indices in the Soybean¹

Abstract

Estimates of genetic similarity or distance between populations or strains of plants are useful in planning crosses for hybrid or pureline cultivar development. We compared coefficients of parentage (r) and similarity indices (s, sz, and sM, based on 20, 13, and 7 genetic loci, respectively) for combinations of 115 soybean [Glycine max (L.) Merr.] cultivars and ancestral introductions. Correlations between r and s were higher than those between r and sz or sM, primarily because s includes information from more loci. The correlation between r and s was higher for the group of soybean cultivars released in the 1970s than for earlier cultivar groups, primarily because of the greater importance of identity by descent relative to identity in phenotype in determining s. The most useful estimate of genetic relationship is a composite index that includes both r and s.

The relationship between parental genetic or phenotypic divergence and progeny variation in the maize nested association mapping population

“…Maximizing genetic variance results in higher power of QTL detection. Theoretically, progeny variance is increased in crosses between genetically more distant parents because the number of segregating loci is maximized (Cox et al, 1984). Studies in wheat (Triticum aestivum), oat (Avena sativa) and soybean (Glycine max) suggest that pedigree divergence between parents, estimated on the basis of the coefficient of parentage (Kempthorne, 1969), could be used to predict genetic variance in F 2 or later segregating generations (Bhatt, 1970(Bhatt, , 1973Cowen and Frey, 1987;Manjarrez-Sandoval et al, 1997).…”

Genetic similarity among soybean (Glycine max (L) Merrill) cultivars released in Brazil using AFLP markers

“…Genetic diversity between individuals may be directly estimated by using biochemical and molecular markers, although the use of biochemical markers, such as isoenzymes, has been hindered in soybean by the low degree of polymorphism in this specie (Cox et al, 1985). This problem has been overcome by using molecular markers.…”

Genetic diversity in sugarcane varieties in Brazil based on the Ward-Modified Location Model clustering strategy

“…Accordingly, the SAS software version 9.1.3 (SAS, 2002) was employed using the "proc inbreed" procedure. For the remote ancestors, f was considered to be equal to zero, as suggested by Cox et al (1985), and the coefficient of endogamy equal to zero was assigned to each genotype, considering the heterozygous trait of this crop (Deren, 1995 …”